Abrading apparatus for use in well bores



Feb. 28, 1967 w. n. OWSLEY ABRADING APPARATUS FOR USE IN WELL BORES Filed Feb. 8, 1965 2 Sheets-Sheet l WILLIAM D. OWSLEY Feb. 28, 1967 w. D. OWSLEY ABRADING APPARATUS FOR USE IN WELL BORES 2 Sheets-Sheet 2 Filed Feb. 8, 1965 \NVENTOR wmmm 0. OWSLEY ATTORNEYS...

United States Patent 3,306,364 ABRADING APPARATUS FOR USE IN WELL BORES William D. Owsley, Duncan, 0kla., assignor to Halliburton Company, Duncan, Okla., a corporation of Delaware Filed Feb. 8, 1965, Ser. No. 431,101 8 Claims. (Cl. 166-173) This invention pertains to an abrading apparatus for use in well bores. In particular, it relates to a well bore scratcher adapted to be reciprocated axially of a well bore.

The drilling and completion of wells, such as oil, gas or water wells, frequently entails the cementing of well liners to a formation. In order to provide an effective bond between well cement and a formation wall, it frequently is desirable to abrade the formation face so as to remove foreign material. Such material usually comprises caked sediment from drilling fluids such as drilling mud.

A variety of well wall scratching, i.e. abrading devices, have been developed. However, in general these .devices have been characterized by structural complexity which made their assembly, maintenance and repair diificult or cumbersome. In addition, such devices have often been excessively vulnerable to damage during abrading operations.

It is an object of the present invention to provide an improved abrading apparatus for use in a well bore which substantially overcomes or minimizes problems of the type heretofore noted.

It is a particular object of the invention to provide such an improved apparatus which is characterized by a minimal number of components which may be conveniently and rapidly assembled even by relatively unskilled personnel.

It is a related object of the invention to provide such an improved apparatus containing components which may be secured without resorting to separate holding elements, clips, etc. and which may be assembled by relatively simple tools.

It is also an object of the invention to provide such improved apparatus which includes abrading elements each comprising a plurality of well wall abrading fingers which are so mounted upon associated body means as to provide resilient means tending to resiliently impede the transmittal of force from one finger to another.

A still further object of the invention is to provide such an apparatus wherein radially inwardly directed force imposed upon the abrading apparatus in use in a well bore will tend to intensify the securing of abrading elements to associated body means.

Yet another object of the invention is to provide such an apparatus wherein securing means which tend to affix abrading elements to associated body means project radially outwardly beyond the body means so as to provide resilient abutments tending to protect the body means and its associated structure from radially inwardly directed forces.

It is also an object of the invention to provide such an improved abrading apparatus wherein securing means resiliently urge abrading elements into engagement with associated body means so as to maintain an effective, abrading element securing action.

Yet another object of the invention is to provide an improved apparatus which is characterized by overall structural simplicity, but operational ruggedness and dependability.

In order to accomplish the foregoing objects, there is provided through this invention an abrading apparatus for use in a well bore, which apparatus comprises body means and securing means for holding the .body means on the 3,306,364 Patented Feb. 28, 1967 outer periphery of conduit means. The body means includes portions defining aperture means. The appa ratus includes at least one abrading element comprising surface abrading means and resilient means. Abutment means extend from the resilient means and are connected with the surface abrading means.

Each such abrading element as described above is mounted on the associated body means with the resilient means thereof disposed at least in part on one side of the body means and the abutment means thereof disposed on an opposite side of the body means. The resilient means extends at least in part through at least a portion of the aperture means. The resilient means has a portion larger than this aperture means portion on said one side of said body means in a direction extending transversely of the aperture means portion. This larger portion of the resilient means is yieldably and resiliently contractable so as to be movable through said aperture means portion.

An independently significant aspect of the invention involves the structure of individual abrading elements as heretofore described and a contractable loop structure which provides said resilient means.

In describing the invention reference will be made to a preferred embodiment illustrated in the appended drawrngs.

In the drawings:

FIGURE 1 is a fragmentary, elevation view of a portion of a conduit string upon which an abrading apparatus of this invention is mounted;

U FIIIGURE 2 is a plan view of the assembly shown in FIG- FIGURE 3 is an enlarged, sectional and elevational view of a portion of the FIGURE 1 assembly as viewed along the section line 33 of FIGURE 2;

FIGURE 4 is a fragmentary, sectional view of a portion of the FIGURE 1 assembly as viewed along the view direction 44 of FIGURE 1; and

FIGURE 5 is an enlarged, elevational view of an individual abrading element incorporated in the FIGURE 1 assembly.

FIGURE 1 illustrates a portion of conventional well conduit means such as a casing or tubing string 1 upon which an abrading apparatus 2, i.e., a well scratcher, is mounted.

As will be appreciated, a plurality of well scratchers 2 may be supported upon conduit string 1 and axially spaced along this string.

Well scratcher 2 includes, as its major components, body means 3 and abrading elements 4.

As shown in FIGURES 1 and 2, abrading elements 4 are mounted upon body means 3 so as to be generally uniformly and circumferentially spaced around conduit string 1.

Body means 3 is fabricated from two or more arcuate, collar-like segments. As shown in FIGURE 2, semicylindrical collar segments 5 and 6 are interconnected by conventional strip hinge units 7 and 8.

Body segments 5 and 6 may be permanently connected by hinge 7, with hinge 8 providing a selectively releasable coupling. Thus, as shown in FIGURES 1 and 2, aligned hinge sections 8a and 811 may be interconnected by a hinge pin 80. This hinge pin may include an abutment 8d to prevent the pin 8!: from moving downwardly out of the aligned openings of the interconnected hinge sections 8a and 8b.

With the hinge connecting arrangement shown in FIG- URES 1 and 2, body segments 5 and 6 may be closed in coaxial encircling engagement around conduit string 1 and be secured in position by the insertion of hinge pin 8c.

In describing the relationship between abrading elements 4, the body means 2, and the conduit means 1, reference will often be made only to the representative body segment 6. It will be understood, however, that references made in connection with the body segment 6 are equally applicable to corresponding structure associated with the body segment 5.

Each body segment has a vertical cross-section as generally shown in FIGURES 1 and 3 including a recessed portion which, in cooperation with the conduit string 1, defines a space between the body segment and the outer periphery 1a of the conduit string 1. Thus, as shown in FIGURE 3, the body segment 6 includes a recessed portion 6a which provides a generally semi-cylindrical cavity 9 disposed between the outer periphery 1a of the conduit string 1 and the inner wall portion 6]; of the portion 6a of the body segment 6.

Wedge means may be provided to coact with the body segments and 6 and the outer periphery 1a of the conduit means 1 so as to positively secure the assembled body means 2 in a fixed position on the conduit string 1.

As shown in FIGURE 1, the wedge means may comprise generally semi-conical wall portions 6c and 6d in the lower portion of body segment 6. As illustrated in FIGURES 1 and 4, wall portions 6c and 6d slope progressively radially outwardly in a direction toward segment openings 62 and 6 respectively. As shown, a segment opening 6g extends between and connects openings 6e and 6 A segment wall 611 in which opening 6g is formed and from which wall portions 60 and 6d are deflected is substantially contiguous with conduit string periphery 1a in the assembly shown in FIGURES 1 and 4. Wedge means such as conventional cement nails, which may have spirally grooved outer peripheries, may be inserted into the openings 62 and 6 and wedged between the wall portions 60 and 6d and the outer periphery 1a of the conduit string to tightly wedge the body means in a fixed position on the conduit means 1, restrained against either axial or rotary movement. Thus, as shown in FIGURE 4, wedging nails 10 and 11 have been inserted into the body segment openings 6e and 6] so as to be wedged, respectively, between the segment wall 6c and the conduit periphery 1a and between the segment wall 6d and the conduit periphery 1a. A similar wedging arrangement, not shown, may be utilized in conjunction with the other body segment 5.

As shown in FIGURE 5, each abrading element is fabricated as a unitary, resilient, wire-like member. Each abrading element would ordinarily be fabricated of spring steel wire. As will be apparent by reference to FIGURE 1, the representative abrading element 4 shown in FIG- URE 5 is disposed in substantially the same elevational position as it occupies in the assembly of FIGURE 1.

Each abrading element 4 as shown in FIGURE 5 includes paired abrading fingers 12 and 13 which provide well wall or well surface abrading means.

A generally helical loop portion 14 provides resilient fastening and stress releasing means in each abrading element 4. Essentially linear, abutment defining, connecting portions 15 and 16 extend in generally opposite directions away from the loop portion 14. In the FIGURE 1 assembly, connecting portion 15 extends from the lower side 14a of the loop portion 14 generally upwardly away from the loop portion 14. Connecting portion 16 extends generally downwardly from the upper portion 14b of loop portion 14. Loop portions 14a and 14b cross and preferably are contiguous at the base of the loop 14 where they merge into the connecting portions 15 and 16.

The looping axis 140 of the loop portion 14 extends generally transversely of the linear axes 15a and 16a of the connecting portions 15 and 16, respectively. Thus, an axial force exerted on either connecting portion in a direction away from the loop portion 14 will tend to cause resilient tightening or contraction of the loop portion 14.

A helical coil 17 connects finger 13 with connecting portion 15 while another helical coil 18 serves to connect finger 12 with connection portion 16.

Finger 13 includes a base portion 13a which extends from the helical coil 17 and an outermost, deflected, well wall engaging end 13b. Similarly, finger 12 includes a base portion 12a extending from coil 18 and a deflected, well wall engaging free end 12b. As shown with reference to FIGURE 2, finger portions 12b and 13b are deflected upwardly with reference to a well bore installation such that their linear axes are generally coplanar with planes extending through the linear axes of intermediate finger portions and 130, respectively, and are parallel with a common central axis of the conduit means 1 and the assembled body means 3.

As illustrated, the coil axis 17a of helical coil 17 and the coil axis 18a of helical coil 18 extend generally transversely of the linear axes of the fingers 12 and 13 and the loop axis 140. As is further apparent by reference to FIGURE 3, the base 13a of the finger 13 adjacent the coil 17 and the base 12a of the finger 12 adjacent the coil 18 are disposed in substantially flush relationship with the adjacent outer periphery of the body means 3 when the individual scratcher 4 is assembled for use as shown in FIGURE 1. Further, the finger base portions 13a and 12a are radially disposed between the radially outward extremity 14d of the loop portion 14 and the outer periphery 1a of the conduit means 1 when the abrading element 4 is mounted as shown in FIGURES 1 and 3.

Each body segment 5 and 6 is provided with a plurality of aperture groupings 19. Aperture groupings 19 are circumferentially spaced about the conduit means 3 when the body means 2 is secured thereon in the assembled position shown in FIGURE 1. Each such grouping comprises three circular apertures 20, 21 and 22 which are spaced along an axis generally parallel with the central, common axis of the body means 3 and the conduit means 1. As illustrated in connection with the body segment 6, the apertures 20, 21 and 22 are formed in the recessed body segment portions such as the portion 6a of the segment 6. These apertures comprise means for mounting the abrading elements in a fashion which will now be described.

Each abrading element is mounted on the body means 3 so that its resilient loop portion 14 has the major portion thereof disposed on the radially outward side of the body means 3. Thus, as shown in FIGURE 3, the loop portion 14 of the abrading element 4 has its major portion, including the outer extremity 14d, positioned on the radially outward side 60 of the segment 6.

The abutment defining connecting means of each abrading element are disposed on the radially inward side of the body means 3 so as to be located between the body means and the outer periphery 1a of the conduit means 1. Thus, as shown in FIGURE 3, the abutment defining connecting portions 15 and 16 are disposed between the inner wall 6a of the body segment 6 and the outer periphery 1a of the conduit string 1.

As shown in connection with FIGURE 3, each resilient means defining, loop 14 projects generally radially outwardly from the common central axis of the conduit string 1 and the assembled body means 3 and projects at least in part through a central aperture 21. The outer diameter d of the loop portion 14, in the relaxed, i.e. unstressed, condition of the loop 14, exceeds the diameter of the circular aperture 21. Thus, the loop 14 is larger in a dimension extending transversely of the aperture 21 than the portion of the aperture 21 through which it extends. However, the loop portion 14 is yieldably and resiliently contractable, owing to the spring-like character of the material from which the element 4 is fabricated, so as to enable the loop 14 to be drawn or snapped through the aperture 21. Thus, when the abrading apparatus is being initially assembled and before it is mounted on the conduit string 1, hook-like tools may be inserted through the apertures 21 and engaged with loop elements 14 and drawn back through the apertures 21 so as to move the loops to the representative position shown in FIGURE 3. In this position, the loop has reexpanded and the loop portions 14e and 14] are engageable or engaged with generally diametrically opposite edge portions 21a and 21b of the central aperture 10. This loop expansion may take place with the loop portion 14 not being allowed to assume its fully relaxed condition. In this event, the engagement of the loop base portions 14e and 14 with the aperture edges 21a and 21b, prior to full loop enlargement, will resiliently cam the loop 14 radially outwardly so as to resiliently urge the connecting portions 15 and 16 into abutting engagement with the inner surface 6a of the body segment 6. In any even, the loop 14 will be engageable with the segment outer periphery 60 so as to secure the element 4, with the loop 14 and the connecting portions 15 and 16 functioning as securing abutments disposed on opposite sides of the segment 6.

As illustrated in FIGURE 3, in connection with representative abrading element 4, connecting portion 15 extends generally toward the uppermost aperture 20 while connecting portion 16 extends generally toward the lowermost aperture 22. Helical coil 17, which interconnects connecting portion 15 and finger 13 is disposed in generally radial alignment with circular aperture 20 with the finger 13 projecting generally outwardly and angularly away from the aperture 20. Similarly, the helical coil portion 18 which interconnects connecting portion 16 and finger 12 is disposed in generally radial alignment with the circular aperture 22 with the finger 12 projecting generally outwardly and angularly away from this aperture. As shown, the coils 17 and 18 may be somewhat smaller in diameter than the apertures 20 and 22 so as to be freely nested in the apertures 20 and 22.

With the apparatus assembled as shown in FIGURES 1 and 2, coil portions 17 and 18 have their coil axes 17a and 18a extending generally radially of the conduit means 1 and body means 2. With the loop 14 of an element 4 engaging the edges of the aperture 21, the radial alignment, i.e. centering, of the coil portions of the abrading element and their associated apertures is automatically facilitated.

As illustrated in FIGURES 2 and 3, the fingers 12 and 13 may be inclined at difierent angles with respect to the radial axes of their respectively associated apertures 22 and 20.

Abrading fingers 12 and 13, of course, will be of such length as to terminate on the periphery of a circle having a radius exceeding that of .a well bore wall portion to be abraded. Thus, for example, where a well bore having a diameter of about 8% inches is being abraded, the abrading fingers 12 and 13 may'terminate at a radius of about 6 inches from the central axis of the conduit means upon which they are mounted.

The resilient loop portions 14 of theabrading elements 4 project radially outwardly beyond the radially outermost extremities of the body segments 5 and 6, the hinges 7 and 8, the wedging nails 10 and 11 and the coils 17 and 18 as generally shown in FIGURES 2 and 3.

As will be appreciated, with the generally radially projecting character of the loops 14, a force directed radially inwardly of the scratcher will tend to flatten and thus transversely enlarge the loops 14 with reference to the mounting aperture 21. In this connection, it should be noted that in the illustrated embodiment, the width of the space 9 is sufiiciently narrow as to positively insure that the base of the loop 14 and the abutment portions 15 and 16 will engage the conduit periphery 1a so as to prevent the loop from being pushed through the aperture 21 in response to such an applied force.

With a conduit string provided with one or more abrading assemblies such as that shown in FIGURE 1 and positioned in a Well bore, vertical reciprocation of the conduit string will cause the abrading fingers to engage and scratch and abrade a formation face. This abrading action is facilitated by the springy character of the abrading fingers.

With the structure and mode of operation of the abrading apparatus having been described, several advantages of the invention have been made apparent.

While abrading is taking place or while a conduit string is being rotated as, for example, while being loaded into a well, it is possible for individual fingers to be subjected to an outward pulling force when they become engaged or caught on well bore portions. Should such pulling result on an individual finger, the pulling force, if sufficient, may be transmitted through the connecting portion associated with the finger to the loop 14 of the abrading element. This force will tend to cause resilient contraction of the loop 14. This contraction may advantageously prevent the transmission of finger-damaging force to the other finger of the abrading element 4.

During abrading operations or while a conduit string is being lowered or raised in a well bore or rotated, the abrading assembly may be forced against adjacent well bore portions. Should such contact occur, a radially inwardly directed force will be imposed against the outermost radial extremity of the assembly at the contact point. As previously noted, this outermost extremity will comprise one or more loops 14 depending upon the circumferential extent of the contact. When such contact occurs, the contacted loops 14 will tend to flatten so as to improve their holding action. In addition, their resilience may be such as to prevent the transmission of crushing or damaging force to other portions of the abrading apparatus including body segments, connecting hinges, wedge pins, helical coils, etc.

The resilient engagement of the loop 14 with the aperture 21 provides a resilient or biasing type of holding action tending to securely hold the abrading elements in engagement with their associated body segments, and additionally, automatically centers the coils 17 and 18 in relation to their apertures 20 and 22. This resilient holding action may tend to prevent wear or damage which would result from excessively loosely mounted finger element.

The use of the loop 14 and the apertured body segments provides a uniquely simplified abrading apparatus assembly involving a minimum number of parts and minimized and simplified fabrication techniques. Assembly of the apparatus elements 4 and the body segments is accomplished by merely snapping, i.e. pulling, the loops 14 through the apertures 21. This arrangement, of course, facilitates not only the original assembly of the apparatus but the subsequent replacement of damaged abrading elements when necessary.

In describing the invention, reference has been made to a preferred and highly advantageous embodiment. However, those skilled in the well cleaning or well wall abrading art and familiar with the disclosure of this invention may envision additions, deletions, substitutions or other modifications which would fall within the purview of the invention as defined in the appended claims.

I claim:

1. An abrading apparatus for use in a well bore, said apparatus comprising:

body means; securing means for holding said body means on the outer periphery of conduit means; said body means having portions defining aperture means; at least one abrading element comprising flexible, surface abrading means, resilient means, abutment means extending from said resilient means and connected with said surface abrading means; said abrading element being mounted on said body means with the resilient means thereof disposed at least in part on one side of said body means,

the abutment means disposed on an opposite side of said body means, and

said resilient means extending at least in part through at least a portion of said aperture means,

having a portion larger than said aperture means portion on said one side of said body means in a direction extending transversely of said aperture means portion, with said larger portion of said resilient means being yieldably and re siliently contractable so as to be movable through said aperture means portion.

2. An apparatus as described in claim 1 wherein: said body means comprises a plurality of arcuate, collar-like segments,

said securing means comprises hinge means interconnecting said collar segments,

and

wedge means adapted to be wedgingly disposed between said body means and the outer periphery of said conduit means;

wherein said aperture means includes a plurality of aperture groupings, said groupings being circumferentially spaced about said conduit means when said body means is mounted thereon, and each said grouping comprising three apertures spaced along an axis generally parallel with the central axis of said body means when mounted on said conduit means;

wherein said abrading apparatus includes a plurality of abrading elements, each of which elements comprises a unitary, resilient, wire-like member, each such member including a pair of spaced, surface abrading fingers providing said surface abrading means,

a generally helical, loop portion providing said resilient means,

a pair of generally linear connecting portions extending in generally opposite directions from said loop portion and providing said abutment means,

one of said connecting portions being connected with one of said surface abrading fingers and the other of said connecting portions being connected with the other of said abrading fingers,

the axis of looping of said loop portion extending generally transversely of the linear axes of said connecting portions whereby an axial force exerted on either of said connecting portions away from said loop portion tends to cause resilient, contraction of said loop portion, and

a coiled portion connecting each surface abrading finger with its associated connecting portion; each said abrading element being mounted on said body means in association with one aperture grouping whereby, with said body means mounted on said conduit means, the loop portion thereof projects generally radially outwardly from said conduit means, extends in part through an intermediate aperture of said aperture groupings and engages generally oppositely disposed edge portions of said intermediate aperture,

said connecting portions extend in generally opposite directions from said loop portion and are disposed between said body means and the outer periphery of said conduit means with one connecting portion extending toward a second aperture of said grouping on one side of said intermediate aperture and the other connecting portion extends generally toward a third aperture of said grouping on an opposite side of said incoiled portion projecting generally outwardly from said second aperture and the other coiled portion is disposed in generally radial alignment with the third aperture of said grouping with the finger attached to said other coiled portion projecting generally outwardly from said third aperture, and

each of said coiled portions has a coil axis extending generally radially of said conduit means.

3. An abrading apparatus as described in claim 2 wherein, with said body means mounted on said conduit means, said p portions of said abrading elements project radially outwardly beyond the radially outward extremities of said body means, said securing means and said coiled portions of said abrading elements.

47 An abrading apparatus as described in claim 3 wherein force applied radially inwardly toward said loop portions of said abrading elements mounted on said conduit means tends to enlarge said loop portion transversely of said radially applied force.

5. In an apparatus as described in claim 1 wherein said body means comprises a plurality of arcuate, collar-like segments, and wherein said aperture means include a plurality of aperture groupings, said groupings being circumferentially spaced about said conduit means when said body means is mounted thereon, and each said grouping comprising three apertures spaced along an axis generally parallel with the central axis of said body means when mounted on said conduit means, and wherein said abrading apparatus includes a plurality of abrading elements, the improvement residing in the structure of each such element, which structure comprises a unitary, resilient, wire-like member, each such member including a pair of spaced, surface abrading fingers providing said surface abrading means,

a generally helical, loop portion providing said resilient means,

a pair of generally linear connecting portions extending in generally opposite directions from said loop portion and providing said abutment means,

one of said connecting portions being connected with one of said surface abrading fingers and the other of said connecting portion being connected with the other of said abrading fingers,

the axis of looping of said loop portion extending generally transversely of the linear axes of said connecting portions whereby an axial force exerted on either of said connecting portions away from said loop portion tends to cause resilient, contraction of said loop portion, and

a coiled portion connecting each surface abrading finger with its associated connecting portion;

each said abrading element being adapted to be mounted on said body means in association with one aperture grouping whereby, with said body means mounted on said conduit means,

the loop portion thereof projects generally radially outwardly from said conduit means, extends in part through an intermediate aperture of said aperture groupings and engages generally oppositely disposed edge portions of said intermediate aperture,

said connecting portions extend in generally opposite directions from said loop portion and are disposed between said body means and the outer periphery of said conduit means with one connecting portion extending toward a second aperture of said grouping on one side of said intermediate aperture and the other connecting portion extends generally toward a third aperture of said grouping on an opposite side of said intermediate aperture,

one coiled portion is disposed in generally radial alignment with said second aperture of said grouping with the finger attached to said one coiled portion projecting generally outwardly from said second aperture and the other coiled portion is disposed in generally radial alignment with the third aperture of said grouping with the finger attached to said other coiled portion projecting generally outwardly from said third aperture, and

each of said coiled portions has a coil axis extending generally radially of said conduit means.

6. An abrading apparatus as described in claim wherein, with said body means mounted on said conduit means, said l-oop portions of said abrading elements project radially outwardly beyond the radially outward extremities of said body means, said securing means and said coiled portions of said abrading elements.

7. An abradin-g apparatus as described in claim 6 wherein force applied radially inwardly toward said loop portions of said abrading elements mounted on said conduit means tend to enlarge said loop portion transversely of said radially applied force.

8. In an abrading apparatus for use in a well =bore,'

which apparatus comprises body means and body means portions defining aperture means, the improvement comprising:

at least one a'brading element comprising flexible, surface abrading means, resilient means, abutment means extending from said resilient means and connected with said surface abrading means;

said abrading element being adapted to be mounted on said body means with the resilient means thereof disposed at least in part on one side of said body means,

the abutment means disposed on an opposite side of said body means, and

said resilient means extending at least in part through at least a portion of said aperture means, having a portion larger than said aperture means portion on said one side of said body means in a direction extending transversely of said aperture means portion, with said larger portion of said resilient means being yieldably and resiliently contractable so as to be movable through said aperture means portion.

References Cited by the Examiner UNITED STATES PATENTS 2,412,876 12/1946 Edwards 166-173 2,671,515 3/1954 Hall 166173 2,990,884 7/1961 Hall et a1. 166173 3,068,941 12/1962 Kluck 166173 3,070,168 12/1962 Sol-um et a1. 166-173 3,071,191 1/1963 Hall et a1. 166-173 CHARLES E. OCONNELL, Primary Examiner.

D. H. BROWN, Assistant Examiner. 

8. IN AN ABRADING APPARATUS FOR USE IN A WELL BORE, WHICH APPARATUS COMPRISES BODY MEANS AND BODY MEANS PORTIONS DEFINING APERTURE MEANS, THE IMPROVEMENT COMPRISING: AT LEAST ONE ABRADING ELEMENT COMPRISING FLEXIBLE, SURFACE ABRADING MEANS, RESILIENT MEANS, ABUTMENT MEANS EXTENDING FROM SAID RESILIENT MEANS AND CONNECTED WITH SAID SURFACE ABRADING MEANS; SAID ABRADING ELEMENT BEING ADAPTED TO BE MOUNTED ON SAID BODY MEANS WITH THE RESILIENT MEANS THEREOF DISPOSED AT LEAST IN PART ON ONE SIDE OF SAID BODY MEANS, THE ABUTMENT MEANS DISPOSED ON AN OPPOSITE SIDE OF SAID BODY MEANS, AND SAID RESILIENT MEANS EXTENDING AT LEAST IN PART THROUGH AT LEAST A PORTION OF SAID APERTURE MEANS, HAVING A PORTION LARGER THAN SAID APERTURE MEANS 